SSJ API Documentation
Stochastic Simulation in Java
Loading...
Searching...
No Matches
umontreal.ssj.probdist.UniformDist Class Reference

Extends the class ContinuousDistribution for the uniform distribution [96]  (page 276) over the interval. More...

Inheritance diagram for umontreal.ssj.probdist.UniformDist:
umontreal.ssj.probdist.ContinuousDistribution umontreal.ssj.probdist.Distribution

Public Member Functions

 UniformDist ()
 Constructs a uniform distribution over the interval \((a,b) = (0,1)\).
 UniformDist (double a, double b)
 Constructs a uniform distribution over the interval \((a,b)\).
double density (double x)
 Returns \(f(x)\), the density evaluated at \(x\).
double cdf (double x)
 Returns the distribution function \(F(x)\).
double barF (double x)
 Returns the complementary distribution function.
double inverseF (double u)
 Returns the inverse distribution function \(x = F^{-1}(u)\).
double getMean ()
 Returns the mean.
double getVariance ()
 Returns the variance.
double getStandardDeviation ()
 Returns the standard deviation.
double getA ()
 Returns the parameter \(a\).
double getB ()
 Returns the parameter \(b\).
void setParams (double a, double b)
 Sets the parameters \(a\) and \(b\) for this object.
double[] getParams ()
 Return a table containing the parameters of the current distribution.
String toString ()
 Returns a String containing information about the current distribution.
Public Member Functions inherited from umontreal.ssj.probdist.ContinuousDistribution
double inverseBrent (double a, double b, double u, double tol)
 Computes the inverse distribution function \(x = F^{-1}(u)\), using the Brent-Dekker method.
double inverseBisection (double u)
 Computes and returns the inverse distribution function \(x = F^{-1}(u)\), using bisection.
double getXinf ()
 Returns \(x_a\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\).
double getXsup ()
 Returns \(x_b\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\).
void setXinf (double xa)
 Sets the value \(x_a=\) xa, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\).
void setXsup (double xb)
 Sets the value \(x_b=\) xb, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\).

Static Public Member Functions

static double density (double a, double b, double x)
 Computes the uniform density function \(f(x)\) in ( funiform ).
static double cdf (double a, double b, double x)
 Computes the uniform distribution function as in ( cdfuniform ).
static double barF (double a, double b, double x)
 Computes the uniform complementary distribution function.
static double inverseF (double a, double b, double u)
 Computes the inverse of the uniform distribution function ( cdinvfuniform ).
static double[] getMLE (double[] x, int n)
 Estimates the parameter \((a, b)\) of the uniform distribution using the maximum likelihood method, from the \(n\) observations.
static UniformDist getInstanceFromMLE (double[] x, int n)
 Creates a new instance of a uniform distribution with parameters.
static double getMean (double a, double b)
 Computes and returns the mean \(E[X] = (a + b)/2\) of the uniform distribution with parameters \(a\) and \(b\).
static double getVariance (double a, double b)
 Computes and returns the variance \(\mbox{Var}[X] = (b - a)^2/12\) of the uniform distribution with parameters \(a\) and \(b\).
static double getStandardDeviation (double a, double b)
 Computes and returns the standard deviation of the uniform distribution with parameters \(a\) and \(b\).

Detailed Description

Extends the class ContinuousDistribution for the uniform distribution [96]  (page 276) over the interval.

\([a,b]\). Its density is

\[ f(x) = 1/(b-a) \qquad\mbox{ for } a\le x\le b \tag{funiform} \]

and 0 elsewhere. The distribution function is

\[ F(x) = (x-a)/(b-a) \qquad\mbox{ for } a\le x\le b \tag{cdfuniform} \]

and its inverse is

\[ F^{-1}(u) = a + (b - a)u \qquad\mbox{for }0 \le u \le1. \tag{cdinvfuniform} \]

Definition at line 44 of file UniformDist.java.

Constructor & Destructor Documentation

◆ UniformDist() [1/2]

umontreal.ssj.probdist.UniformDist.UniformDist ( )

Constructs a uniform distribution over the interval \((a,b) = (0,1)\).

Definition at line 51 of file UniformDist.java.

◆ UniformDist() [2/2]

umontreal.ssj.probdist.UniformDist.UniformDist ( double a,
double b )

Constructs a uniform distribution over the interval \((a,b)\).

Definition at line 58 of file UniformDist.java.

Member Function Documentation

◆ barF() [1/2]

double umontreal.ssj.probdist.UniformDist.barF ( double a,
double b,
double x )
static

Computes the uniform complementary distribution function.

\(\bar{F}(x)\).

Definition at line 121 of file UniformDist.java.

◆ barF() [2/2]

double umontreal.ssj.probdist.UniformDist.barF ( double x)

Returns the complementary distribution function.

The default implementation computes \(\bar{F}(x) = 1 - F(x)\).

Parameters
xvalue at which the complementary distribution function is evaluated
Returns
complementary distribution function evaluated at x

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 70 of file UniformDist.java.

◆ cdf() [1/2]

double umontreal.ssj.probdist.UniformDist.cdf ( double a,
double b,
double x )
static

Computes the uniform distribution function as in ( cdfuniform ).

Definition at line 106 of file UniformDist.java.

◆ cdf() [2/2]

double umontreal.ssj.probdist.UniformDist.cdf ( double x)

Returns the distribution function \(F(x)\).

Parameters
xvalue at which the distribution function is evaluated
Returns
distribution function evaluated at x

Implements umontreal.ssj.probdist.Distribution.

Definition at line 66 of file UniformDist.java.

◆ density() [1/2]

double umontreal.ssj.probdist.UniformDist.density ( double a,
double b,
double x )
static

Computes the uniform density function \(f(x)\) in ( funiform ).

Definition at line 94 of file UniformDist.java.

◆ density() [2/2]

double umontreal.ssj.probdist.UniformDist.density ( double x)

Returns \(f(x)\), the density evaluated at \(x\).

Parameters
xvalue at which the density is evaluated
Returns
density function evaluated at x

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 62 of file UniformDist.java.

◆ getA()

double umontreal.ssj.probdist.UniformDist.getA ( )

Returns the parameter \(a\).

Definition at line 233 of file UniformDist.java.

◆ getB()

double umontreal.ssj.probdist.UniformDist.getB ( )

Returns the parameter \(b\).

Definition at line 240 of file UniformDist.java.

◆ getInstanceFromMLE()

UniformDist umontreal.ssj.probdist.UniformDist.getInstanceFromMLE ( double[] x,
int n )
static

Creates a new instance of a uniform distribution with parameters.

\(a\) and \(b\) estimated using the maximum likelihood method based on the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\).

Parameters
xthe list of observations to use to evaluate parameters
nthe number of observations to use to evaluate parameters

Definition at line 188 of file UniformDist.java.

◆ getMean() [1/2]

double umontreal.ssj.probdist.UniformDist.getMean ( )

Returns the mean.

Returns
the mean

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 78 of file UniformDist.java.

◆ getMean() [2/2]

double umontreal.ssj.probdist.UniformDist.getMean ( double a,
double b )
static

Computes and returns the mean \(E[X] = (a + b)/2\) of the uniform distribution with parameters \(a\) and \(b\).

Returns
the mean of the uniform distribution \(E[X] = (a + b) / 2\)

Definition at line 199 of file UniformDist.java.

◆ getMLE()

double[] umontreal.ssj.probdist.UniformDist.getMLE ( double[] x,
int n )
static

Estimates the parameter \((a, b)\) of the uniform distribution using the maximum likelihood method, from the \(n\) observations.

\(x[i]\), \(i = 0, 1, …, n-1\). The estimates are returned in a two-element array, in regular order: [ \(a\), \(b\)]. The maximum likelihood estimators are the values \((\hat{a}\), \(\hat{b})\) that satisfy the equations

\begin{align*} \hat{a} & = \min_i \{x_i\} \\ \hat{b} & = \max_i \{x_i\}. \end{align*}

See [114]  (page 300).

Parameters
xthe list of observations used to evaluate parameters
nthe number of observations used to evaluate parameters
Returns
returns the parameters [ \(\hat{a}\), \(\hat{b}\)]

Definition at line 163 of file UniformDist.java.

◆ getParams()

double[] umontreal.ssj.probdist.UniformDist.getParams ( )

Return a table containing the parameters of the current distribution.

This table is put in regular order: [ \(a\), \(b\)].

Implements umontreal.ssj.probdist.Distribution.

Definition at line 260 of file UniformDist.java.

◆ getStandardDeviation() [1/2]

double umontreal.ssj.probdist.UniformDist.getStandardDeviation ( )

Returns the standard deviation.

Returns
the standard deviation

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 86 of file UniformDist.java.

◆ getStandardDeviation() [2/2]

double umontreal.ssj.probdist.UniformDist.getStandardDeviation ( double a,
double b )
static

Computes and returns the standard deviation of the uniform distribution with parameters \(a\) and \(b\).

Returns
the standard deviation of the uniform distribution

Definition at line 226 of file UniformDist.java.

◆ getVariance() [1/2]

double umontreal.ssj.probdist.UniformDist.getVariance ( )

Returns the variance.

Returns
the variance

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 82 of file UniformDist.java.

◆ getVariance() [2/2]

double umontreal.ssj.probdist.UniformDist.getVariance ( double a,
double b )
static

Computes and returns the variance \(\mbox{Var}[X] = (b - a)^2/12\) of the uniform distribution with parameters \(a\) and \(b\).

Returns
the variance of the uniform distribution \(\mbox{Var}[X] = (b - a)^2 / 12\)

Definition at line 213 of file UniformDist.java.

◆ inverseF() [1/2]

double umontreal.ssj.probdist.UniformDist.inverseF ( double a,
double b,
double u )
static

Computes the inverse of the uniform distribution function ( cdinvfuniform ).

Definition at line 135 of file UniformDist.java.

◆ inverseF() [2/2]

double umontreal.ssj.probdist.UniformDist.inverseF ( double u)

Returns the inverse distribution function \(x = F^{-1}(u)\).

Restrictions: \(u \in[0,1]\).

Parameters
uvalue at which the inverse distribution function is evaluated
Returns
the inverse distribution function evaluated at u
Exceptions
IllegalArgumentExceptionif \(u\) is not in the interval \([0,1]\)

Reimplemented from umontreal.ssj.probdist.ContinuousDistribution.

Definition at line 74 of file UniformDist.java.

◆ setParams()

void umontreal.ssj.probdist.UniformDist.setParams ( double a,
double b )

Sets the parameters \(a\) and \(b\) for this object.

Definition at line 247 of file UniformDist.java.

◆ toString()

String umontreal.ssj.probdist.UniformDist.toString ( )

Returns a String containing information about the current distribution.

Definition at line 268 of file UniformDist.java.


The documentation for this class was generated from the following file: